Planning tool for succession planting of crops, particularly lettuce, broccoli, and corn

View the project final report

Commodities

• Vegetables: broccoli, sweet corn

Practices

• Crop Production: continuous cropping, organic fertilizers
• Education and Training: farmer to farmer, on-farm/ranch research
• Production Systems: organic agriculture

Diversified farms grow many crops. Planning a constant supply of many crops is a challenge because time to maturity varies throughout the season, and there are no planning tools to help growers predict time to harvest. This project will measure the time to harvest for many plantings of 2 varieties of lettuce, one variety of broccoli and one variety of corn and share the raw data and the GDD data with other farmers at a meeting in NH, and in the NH vegetable and Fruit newsletter. Grocery store, farm stand, and restaurant customers want a steady supply of “every” crop. Scheduling plantings for constant supply of crops through the year is a major planning question for growers. As climate change becomes more prevalent, this will become even more important. The main variables are seen to be temperature above the plants “base growing temperature”, and the amount of light as the calendar year progresses. The temperature is the largest variable, year to year. As more growers practice winter growing, these issues will become even more pronounced. Winter growing will not be addressed by this specific proposal, but the methods and equipment should be useful.

We will track the time to grow from seed to harvestable size for 2 varieties of lettuce, one variety of broccoli, and one variety of corn. We will add plantings to the beginning and the end of the year for the purpose of understanding the early and late season issues that will be most affected by temperature and daylight. We will do this for 1 growing season under this proposal. Ideally we would repeat these results over 3 seasons, the following two years would be done under subsequent proposals. The varieties are:

-Lettuce Transplants. Vulcan (Vn) and Greenstar (GSn) ), about 17 to 20 plantings each
-Broccoli Transplants. Everest (En), about 17 to 20 plantings
-Corn transplants, Brocade (Bn), about 7 to 12 plantings (every other week to weekly)

Methods

• For each planting, create two Large water proof markers (labels) that travel with the planting. These will be 8x5 color coded card stock signs that will be laminated. Vulcan will be Red, Greenstar will be Green, Everest will be Yellow, Brocade will be Blue or Red. The Planting number will be on the marker. These will be created by the farmer prior to the season and will be in the transplant schedule packet.

• We will add 1-2 smaller plantings to the beginning, and to the end of the year. These will be 1/4 to ½ the size of the regular plantings and are added to better understand how the crops grow.

• When seeding, both markers are placed in a flat in the planting. The actual date seeded will be recorded on the transplant schedule and the back of the markers. This will be done by whoever is seeding the transplants.

• When Transplanting, one marker is placed at the start of the planting, the other at the end of the planting. The signs will be placed in the field on wire hoops so that they are easy to see. Corn may require poles to hold the signs so that they are visible during harvest. The actual date transplanted will be recorded on the transplant schedule and the back of the markers. This will be done by the driver of the tractor when transplanting.

• When cultivating, the tractor driver will move the markers as needed to mechanically cultivate, and replace exactly. We generally do not cultivate lettuce. When corn is cultivated we will move the markers only as needed for mechanical cultivation. We plan to use plastic for all broccoli.

• When Harvesting, We will record the planting number that was harvested every day that it was harvested. The lettuce harvester will use the pick sheet as the place to record the planting(s) harvested. The lettuce harvester (or farmer) will also record as harvested if the crop is ready, but the market demand does not necessitate the planting to be harvested .

• For Lettuce we will record the harvest date of heads, for Broccoli we will record the harvest date of crowns (not side shoots) and for Corn we will record the harvest of top ears only.

• Lettuce in this study will all be planted on white plastic on a 5 inch high raised bed. 3 rows per bed, 1 ft spacing in row. Except for the plastic, this is standard practice at Blue Ox . The plastic will be used for the entire year so that the conditions are constant, and to keep weed load down. We will use spray irrigation on the lettuce.

• Broccoli in this study will all be planted on White plastic on a 5 inch high raised bed. 2 rows per bed, 1 ft spacing in row. Except for the plastic, this is standard practice at Blue Ox. Spray irrigation.

• Corn will all be grown on bare ground with spray irrigation.
Because we routinely take detailed harvest data as a part of our record-keeping for organic certification, we are comfortable with this level of data collection.

We will have temperature sensors that automatically record the air temperatures at crop height to a database with 1 hour granularity or better. We will also record Soil temperature at each air temperature location. We considered having rain fall, soil moisture, and light intensity measurements, but these measurements are believed to be less valuable, and the cost did not seem to be worth it.
All temperature sensors will be shielded from solar radiation, as per the manufacturer’s recommendations. However we will make the shields rather than purchase them.